U.S. Pat. No. 3,860,358 to Cavicchi et al is directed to a turbine blade tip seal wherein the radius of curvature of the sealing surface changes thereby minimizing blade tip clearance between cold engine conditions and design operating conditions.
In U.S. Pat. No. 3,986,720 to Knudson et al is directed to a turbine shroud structure composed of a material exhibiting a low coefficient of thermal expansion at low temperatures to provide large cold clearances at a high coefficient of thermal expansion at higher temperatures.
U.S. Pat. No. 3,690,785 to Lind is directed to a spring plate sealing system composed of members having different thermal expansion properties so as to provide sealing at high temperatures.